Book Nook is a very simple, but creative bookshelf decoration. It is a book-sized (thick) shelf insert, a mini diorama that gives you a 3D view. You can simply understand as “hollowing out” the book to make a miniature world. DIY Book Nook is originated in 2018 by a Japanese artist named Monde. “Mini Worlds Created Inside Your Bookshelf”. They’re essentially a dollhouse, but just for a book, and they’re pretty charming.